The field of the present invention is air driven double diaphragm pumps employed in high pressure configurations.
Air driven double diaphragm pumps employ a source of pressurized air for operation and are quite versatile in their ability to pump a wide variety of material. Pumps having double diaphragms driven by compressed air directed through an actuator valve are found in U.S. Pat. Nos. 5,957,670; 5,169,296; 4,247,264; Des. 294,946; Des. 294,947; and Des. 275,858. Actuator valves used in such pumps are illustrated in U.S. Published Application No. 2005/0249612; and U.S. Pat. No. 4,549,467. The disclosures of the foregoing patents and published application are incorporated herein by reference.
Common to many air driven diaphragm pumps and as shown in the aforementioned patent publications relating to air driven diaphragm pumps is the presence of an actuator housing having air chambers facing outwardly to cooperate with two pump diaphragms. Pump chamber housings with inlet manifolds and outlet manifolds are also common and arranged outwardly of the pump diaphragms. Ball check valves are positioned in both the inlet passageways and the outlet passageways of the pump chamber housings. A shaft runs through the actuator and the air chambers and is coupled with the diaphragms. An air valve controls flow to alternate air pressure and exhaust to and from each of the air chambers, resulting in reciprocation of the pump. The air valve is controlled by a pilot system controlled in turn by the position of the pump diaphragms. Thus, a feedback control mechanism is provided to convert a constant air pressure into a reciprocating distribution of pressurized air to each air chamber for driving the diaphragms in alternating pumping and suction strokes. A vast range of materials are able to be pumped safely and efficiently using such systems.
The aforementioned systems provide a pumping capacity which is limited to the pressure of the supply air behind each diaphragm. Diaphragm pumps have also been developed which multiply that pressure through additional pistons or diaphragms affixed to the central shaft Such additional pistons or diaphragms contribute a boost in force on the shaft cooperative with the diaphragm defining the pump chamber. Reference is made to U.S. Pat. No. 6,158,982.
An additional such mechanism used for increased pumping pressures employs the described double diaphragm pumps with a rerouting of the air about the pump from the air chamber on one side of the pump to the pump chamber on the other side of the pump. The pump chamber is sealed off at both the intake and exhaust. In this manner both diaphragms exert pumping pressure. The pressurized air in the air chamber adjacent to the pumping chamber provides pressure against the associated diaphragm while the pump chamber which has been converted into an air chamber exerts pressure on the other diaphragm resulting in a force on the shaft extending between diaphragms. In this way, an approximate 2:1 ratio of fluid outlet pressure to inlet air pressure is achieved. In the ducting for air flow to the converted pump chamber, fittings and tubing or hoses are employed from the air chamber to the converted pump chamber. Such apparatus are exposed and vulnerable.